The present invention generally relates to computer apparatus and, in a preferred embodiment thereof, more particularly relates to pointing devices, such as trackballs and mice, for portable computers.
To control the movement of a cursor or other position highlighting indicia along its screen, a conventional portable computer is typically provided with a trackball device, either integral with the computer or of a xe2x80x9cclip-onxe2x80x9d variety. This conventional pointing device has a captively retained ball therein, a portion of which is exposed in a manner permitting the computer user to touch the ball and roll it in any selected direction corresponding to the desired movement direction of the screen cursor. Suitable mechanical-to-electrical transducing circuitry interconnected between the trackball and the computer screen appropriately correlates the movement of the screen cursor to the rotational speed and sense of the ball movement.
Both integral and clip-on trackball devices provide the primary advantage of compactness, permitting the portable computer to be used in cramped spaces, such as on the tray table on the back of an airline seat, without requiring any more horizontal support surface space than that required for the base portion of the computer housing.
However, for most portable computer users a conventional mouse, which may be rolled along a support surface adjacent the computer, is easier to use than a trackball as a pointing device and is therefore preferable. Accordingly, many portable computers are sold with mice instead of trackballs. Despite its ease of use, though, a computer mouse is not always usable in cramped spaces such as on airline seat trays. In such instances, the computer user is relegated to using a trackball pointing device, or the computer keyboard, to control the movement of a screen cursor.
It can be readily be seen from the foregoing that it would be desirable to provide a single computer pointing device that gives a portable computer user both the space compactness of a trackball and the ease of use of a mouse. It is accordingly an object of the present invention to provide such a pointing device.
In carrying out principles of the present invention, in accordance with a preferred embodiment thereof, a reversible trackball/mouse pointing device is provided for controllably moving a cursor image generated on the display screen of a computer. The pointing device comprises a support structure having a side, and a ball rollingly supported within the support structure and having a portion exposed on the side thereof.
The support structure is rotatable about an axis thereof between a first position in which the ball portion may be manually engaged and moved in a manner rotating the ball in a selected direction relative to the support structure, and a second position in which the ball portion may be positioned against a surface and the support structure moved along the surface in a manner causing the ball to be rotated by the surface in a selected direction relative to the moving support structure.
First means are provided for generating first and second output signals respectively indicative of the direction of rotation of the ball relative to the support structure about first and second reference axes, each of the first and second output signals having a directional sense.
Second means are provided for receiving the first and second output signals and responsively generating a third output signal useable to control the movement of the cursor image on the display screen and representing a directional component summation of the first and second output signals.
Third means, responsive to the movement of the support structure from one of the first and second positions thereof to the other of the first and second positions thereof, are provided for reversing the directional component of the third output signal associated with a selected one of the first and second output signals.
Accordingly, in its first position the pointing device is useable as a trackball, and in its second position the pointing device is useable as a mouse. In accordance with one aspect of the present invention, the support structure, in its first or trackball orientation, is removably insertable in an external recess formed in a housing portion of the computer in a manner such that the ball portion is exposed to manual contact by a user of the computer. To convert the pointing device from its trackball orientation to its mouse orientation, the device is simply removed from the external recess, vertically inverted, and placed first side down on a horizontal support surface adjacent the computer housing.
In a preferred embodiment of the pointing device the first and second means include an electronic circuit carried by the support structure and operatively coupled to the ball, and the third means include a mercury switch carried by the support structure and operatively coupled to the electronic circuit.
According to other aspects of the invention the support structure has outwardly projecting ribs on opposite side edge portions thereof, the ribs being slidably receivable in grooves formed in opposing side wall portions of the computer housing recess. The support structure has a first pair of pointer control buttons operatively disposed on its first side, and a second pair of pointer control buttons operatively disposed on its second side, and the computer housing recess has a bottom wall that protectively underlies the second pair of pointer control buttons when the support structure, in its trackball orientation, is inserted into the housing recess.
Representatively, the pointing device is operatively connected to the computer by means of a wire that extends from the support structure into the interior of the computer housing through an opening formed in an inner end wall of the housing recess, the aforementioned third output signal being transmitted to the computer through the wire. It will be appreciated that, if desired, the wire could be eliminated and the pointing device operatively coupled to the computer by a suitable IR or RF transmitter carried by the support structure.
In an alternate embodiment of the pointing device a conventional touch pad is mounted on the side of the support structure opposite the exposed mouse ball portion. The touch pad faces upwardly when the pointing device is operatively inserted, ball side down, into the housing recess and is used in lieu of the inverted trackball mode of the previously mentioned embodiment of the pointing device. Additionally, the directional component reversing portion of the previously mentioned third means are eliminated in this alternate embodiment of the pointing device.